1. Field of the Invention
The present invention relates to a coating composition, and, in particular, to a coating composition with superior storage stability which is suitable for forming a coating film with superior performance on the surface of substrates made of stainless steel, aluminum, ceramics, cement, paper, glass, plastic, inorganic ceramic, and on cloth, or the like.
2. Description of the Prior Art
In recent years there have been increased requirements for a coating composition which can form a coating film with a high degree of hardness and good adherence, superior in resistance to heat, moisture, staining, organic chemicals, acids, alkalis, corrosion, abrasion, weathering, humidity, and the like.
A portion of the above-mentioned requirements has been satisfied by the provision of a coating composition as disclosed in Japanese Patent Laid-open (ko-kai) No. 135465/1985, comprising a dispersion of a partial condensate of an organosilane with a colloidal silica and a silicon-denatured acryl resin; a coating composition as disclosed in Japanese Patent Laid-open (ko-kai) No.1769/1989 comprising a composition formed from a condensation product of an organosilane with a chelated zirconium alkoxide compound and a vinyl resin containing a hydrolyzable silyl group; or a coating composition as disclosed in U.S. Pat. No. 4,904,721 comprising a composition formed from a condensate of organosilane, colloidal alumina and a vinyl resin containing hydrolyzable silyl group.
However, in coating films formed using the coating compositions disclosed in Japanese Patent Laid-open (ko-kai) No. 135465/1985 and U.S. Pat. No. 4,904,721, the glossiness of the coating film decreases on long-term exposure to ultraviolet radiation.
The composition disclosed in Japanese Patent Laid-open (ko-kai) No. 1769/1989 exhibits inadequate stability in storage and, if its solid content is increased, tends to form a gel over in a short period of time.